JP3849840B2 - Cooling passage structure of internal combustion engine for vehicle - Google Patents

Description

[0001]
[Industrial application fields]
The invention of the present application relates to a cooling passage structure for an internal combustion engine, and more particularly to a cooling passage structure for an internal combustion engine that is suitable for use in a two-cycle two-cylinder internal combustion engine having an integral transmission chamber.
[0002]
[Prior art, problems to be solved by the invention]
2. Description of the Related Art Conventionally, an internal combustion engine of a type integrally having a mission chamber for a motorcycle or the like has a structure in which heat from the mission chamber is directly transmitted to a crank chamber through a case member (refer to Japanese Patent Laid-Open No. 4-232329). ). For this reason, the temperature of the intake air (air-fuel mixture) in the crank chamber rises, and there is a possibility that the intake charging efficiency is reduced and the output is reduced.
[0003]
The invention of the present application solves the above-mentioned problems of the conventional internal combustion engine, prevents heat from the transmission chamber from being transmitted to the crank chamber through the case member, and prevents a rise in the temperature of the intake air in the crank chamber. Thus, it is an object of the present invention to provide a cooling passage structure for an internal combustion engine for a vehicle that is improved in intake charge efficiency and output.
[0004]
[Means for solving the problems and effects]
The invention of the present application relates to a cooling passage structure of an internal combustion engine that solves the above-described problems, and the invention described in claim 1 includes a crank chamber of the internal combustion engine and a rear side of the crank chamber with respect to the traveling direction of the vehicle. A partition wall is formed between the transmission chamber and the integral transmission chamber, from the intake passage side of the internal combustion engine toward the exhaust port side facing the intake passage with respect to the cylinder axis of the cylinder block of the internal combustion engine, A cooling passage structure for an internal combustion engine for a vehicle , characterized in that a cooling water passage is provided so as to surround the crank chamber and flow cooling water facing the partition wall .
[0005]
Since the invention described in claim 1 is configured as described above, the crank chamber is cooled by the cooling water flowing through the cooling water passage surrounding it, and the partition wall between the crank chamber and the transmission chamber is provided. By being cooled by the cooling water, the heat from the transmission chamber is also carried away by the cooling water and transmitted to the crank chamber is greatly reduced. Thereby, the temperature around the crank chamber is stabilized. Further, the temperature around the transmission chamber is also stabilized, and the durability of the transmission mechanism can be improved.
[0006]
Further, by configuring the invention according to claim 1 as described in claim 2, the crank chamber is a crank chamber for a two-cycle internal combustion engine that performs primary compression of the air-fuel mixture. As a result, the temperature around the crank chamber for the two-cycle internal combustion engine is stabilized, so that the temperature rise of the air-fuel mixture in the crank chamber is prevented, the intake charging efficiency is improved, and the output can be improved. .
[0007]
According to a third aspect of the present invention, in the cooling passage structure of the vehicle internal combustion engine according to the first or second aspect, the cooling water passage communicates with a water jacket formed in a cylinder block. According to a fourth aspect of the present invention, in the cooling passage structure for an internal combustion engine for a vehicle according to the third aspect, the cooling water passage is at a position facing the intake passage with respect to the cylinder axis, and the exhaust port. An intermediate water chamber is provided at a position in the vicinity of, and the intermediate water chamber communicates with the water jacket of the cylinder block.
[0008]
According to the fifth aspect of the present invention , a partition wall is formed between a crank chamber of the internal combustion engine and a transmission chamber integrally provided at the rear of the crank chamber in the traveling direction of the vehicle . The crankshaft is placed horizontally in the left-right direction, a cooling air introduction port is provided in front of the crankshaft and on the intake passage side , a cooling air discharge port is provided on the rear side, and the cooling air is supplied from the cooling air introduction port. A cooling passage structure for an internal combustion engine for a vehicle , wherein a cooling air passage for passing cooling air toward the discharge port is provided in contact with the partition wall .
[0009]
Since the invention described in claim 5 is configured as described above, the heat from the primary power transmission chamber in which the mission chamber, the primary gear, and the like are accommodated is carried away by the cooling air and transmitted to the crank chamber. It is suppressed. Thereby, the temperature around the crank chamber is stabilized. Further, the temperature around the transmission chamber is stabilized, which can contribute to the improvement of the durability of the transmission mechanism. Further, since the traveling wind of the vehicle is guided into the cooling air passage from the front cooling air introduction port, it can contribute to the cooling of the crankcase.
[0010]
Further, by configuring the invention according to claim 5 as described in claim 6 , the cooling air passage is arranged in two directions respectively oriented obliquely up and down in front of the traveling direction of the vehicle on which the internal combustion engine is mounted. The cooling air is introduced from the space surrounded by the cylinders, the cooling air is caused to flow along the side of the crank chamber, and the cooling air is discharged in the diagonally upward and downward directions of the crankcase.
[0011]
As a result, the traveling wind can be efficiently guided to the cooling air passage to contribute to the cooling of the crankcase, and the temperature rise of the crank chamber can be further prevented.
[0012]
Further, by configuring the invention of claim 6, wherein as claimed in claim 7 wherein the crankcase is to be a crankcase for two-cycle two-cylinder internal combustion engine for supporting a parallel pair of crankshaft .
[0013]
As a result, a large cooling air inlet can be formed in front of the pair of parallel crankshafts, and sufficient cooling air can be obtained to further prevent a rise in the temperature of the crank chamber. The temperature around the room is further stabilized. Further, since the temperature rise of the crank chamber for the two-cycle two-cylinder internal combustion engine is further prevented, the temperature rise of the air-fuel mixture in the crank chamber is prevented, the intake charging efficiency is improved, and the output is improved. Can do.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
The following describes the implementation form of the invention illustrated in FIGS. 1 to 5.
1 is a left side sectional view of an internal combustion engine to which the cooling passage structure according to the present embodiment is applied, FIG. 2 is a sectional view taken along the line II-II in FIG. 1, and FIG. 3 is a left side cover of the internal combustion engine in FIG. FIG. 4 is a sectional view taken along line IV-IV in FIG. 2, and FIG. 5 is a partial right side view of the internal combustion engine in FIG. FIG. 5 also shows a modification of the cooling passage structure in the present embodiment.
[0015]
1 to 3, an internal combustion engine 1 to which the cooling passage structure in the present embodiment is applied is a spark ignition / water cooling / air cooling type two-cycle V-type two-cylinder internal combustion engine, and the V-type opening direction is set in the vehicle. It is mounted on a motorcycle facing forward, and a transmission 3 is integrally provided behind the internal combustion engine body 2.
[0016]
The first crank chamber 6 on the side of the first cylinder 4 oriented obliquely upward in the front of the internal combustion engine body 2 and the second crank chamber 7 on the side of the second cylinder 5 oriented obliquely downward in the front are brought closer to the V-shaped apex region. The crankcases arranged adjacent to each other and defining the respective chambers are combined to form one unit case 8. This unit case 8 integrally has a mission chamber 9 immediately behind the combined crank chamber in which the first and second crank chambers 6 and 7 are combined.
[0017]
Therefore, the unit case 8 has first and second crank chambers 6 and 7 and a transmission chamber 9 inside thereof, and a large block body having first and second intake passages 10 and 11 on the front and upper sides thereof. As a unit, it is integrally formed by casting and serves as a united crankcase (hereinafter simply referred to as a crankcase) that defines a united crankcase and a transmission case. The first and second intake passages 10 and 11 are disposed in an angular relationship so as to form a V shape opened rearward, and a reed valve is attached to the inlet portion thereof.
[0018]
On the opening sides of the first and second crank chambers 6 and 7 of the unit case 8, mating surfaces A and B are formed, respectively, and the first cylinder on the first cylinder 4 side is formed on these mating surfaces A and B. The block 12 and the second cylinder block 13 on the second cylinder 5 side are connected to each other and are integrally connected by a bolt (not shown). Further, first and second cylinder heads 14 and 15 are integrally connected to the first and second cylinder blocks 12 and 13 by bolts (not shown).
[0019]
When the internal combustion engine 1 is operated, the air-fuel mixture (intake) sucked into the first crank chamber 6 through the first intake passage 10 is primarily compressed here, and the first piston 16 is lowered from within the cylinder bore 56. In the process of rising, the gas is fed into the combustion chamber 18 through the scavenging port 17. At this time, the combustion gas remaining in the combustion chamber 18 is expelled by the entry of a new air-fuel mixture and is discharged from the exhaust port 19.
[0020]
Next, when the first spark plug 20 sparks and ignites the new air-fuel mixture sent into the combustion chamber 18, the air-fuel mixture explodes and the first piston 16 descends. In the lowering process of the first piston 16, the exhaust port The combustion gas is discharged from 19 and a new air-fuel mixture is supplied from the scavenging port 17 to the combustion chamber 18, and the remaining combustion gas in the combustion chamber 18 is scavenged by this new air-fuel mixture.
[0021]
On the other hand, the reciprocating motion from the lowering of the first piston 16 to the rising and from the rising to the lowering is transmitted to the first crankshaft 22 via the first connecting rod 21, and is converted into rotational motion by the first crankshaft 22. Since the operations of the second piston 23, the second connecting rod 24, the second crankshaft 25, and the second spark plug 26 on the second cylinder 5 side are the same, detailed description thereof is omitted.
[0022]
The engine output on the first cylinder 4 side transmitted to the first crankshaft 22 is a first interlocking gear 27 and a second crankshaft 25 that are fixed to a portion protruding from the unit case 8 at one end of the first crankshaft 22. Is engaged with a second interlocking gear 28 fixed to a portion protruding from the unit case 8 at one end of the first drive gear, and a primary drive gear fixed adjacent to the second interlocking gear 28 at the same portion of one end of the second crankshaft 25. 29 is transmitted to the transmission 3 through meshing with a primary driven gear 30 serving as an input gear to the transmission 3.
[0023]
Further, the engine output on the second cylinder 5 side transmitted to the second crankshaft 25 is transmitted to the transmission 3 through meshing of the primary drive gear 29 and the primary driven gear 30.
[0024]
In this way, the engine outputs on both sides of the first and second cylinders 4 and 5 transmitted to the transmission 3 are decelerated based on the reduction ratio due to the engagement of a predetermined gear in the transmission 3, and one end of the countershaft 32 is It is taken out from the sprocket 33 fixed to the portion protruding from the unit case 8. Then, it is transmitted to the rear wheel via a chain suspended between the sprocket 33 and a sprocket (not shown) fixed to the rear wheel of the vehicle.
[0025]
The first and second crankshafts 22 and 25 are horizontally placed in the left-right direction when viewed in the vehicle traveling direction, and are rotatably supported by a crankcase (a crankcase portion of the unit case 8). 34 is a clutch for intermittently transmitting the engine output between the primary driven gear 30 and the main shaft 31 of the transmission 3, and 35 is a shift mechanism for changing the meshing of the gear, and includes a shift fork and a shift cam. Yes.
[0026]
Next, the cooling structure of the internal combustion engine 1 will be described with reference to FIGS. 1, 2, and 5.
The impeller 37 of the cooling water pump 36 is integrated with the portion protruding from the unit case 8 at the other end of the second crankshaft 25 (the end opposite to the side where the second interlocking gear 28 and the primary drive gear 29 are fixed). It is connected to. The impeller 37 is covered with a pump cover 38, and a pump chamber 39 is formed around the impeller 37. Accordingly, the cooling water pump 36 is rotationally driven by the second crankshaft 25.
[0027]
Engine cooling water cooled by a radiator (not shown) is guided into the internal combustion engine 1 by a cooling water pump 36.
The cooling water boosted by the cooling water pump 36 flows into the pump discharge passage 40 formed in the right wall of the unit case 8 and flows there, as shown in FIG. It flows into the inlet water chambers 41 and 42 that form the start ends of the cooling water passages 43 and 44 that surround the first and second crank chambers 6 and 7. Then, the partition wall 55 that flows along the periphery of the first and second crank chambers 6 and 7 and cools the space between the first and second crank chambers 6 and 7 and the transmission chamber 9 is cooled. As a result, heat from the transmission chamber 9 toward the first and second crank chambers 6 and 7 is blocked, and the temperatures of the first and second crank chambers 6 and 7 are stabilized, and are sucked into these chambers to be primary. The temperature rise of the compressed air-fuel mixture is prevented. The passages 40 to 44 through which the cooling water flows are all marked with coarsely distributed points.
[0028]
The cooling water that has flowed along the periphery of the first and second crank chambers 6 and 7 through the cooling water passages 43 and 44 is then on the side of the unit case 8 that is substantially opposite to the first and second intake passages 10 and 11. Flow into the intermediate water chambers 45 and 46 formed in the vicinity of the mating surfaces A and B, respectively. Then, the first and second cylinder blocks 12, 13 and the first and second cylinder heads 14 exit from these intermediate water chambers 45 and 46 and pass through a communication passage provided through the mating surfaces A and B. , 15 are fed into water jackets 47, 48 formed in communication with each other to cool the first and second cylinder blocks 12, 13, the first and second cylinder heads 14, 15. And it flows in into radiator inlet piping from the cooling water outlets 49 and 50 formed in the 1st and 2nd cylinder heads 14 and 15, respectively, is cooled in a radiator, and recirculates in the internal combustion engine 1 again.
[0029]
As shown in FIG. 5, a cooling water passage 51 that short-circuits between the inlet water chamber 41 and the intermediate water chamber 45, and a cooling water passage 52 that short-circuits between the inlet water chamber 42 and the intermediate water chamber 46. May be formed on the right wall of the unit case 8 so as to circulate around the first and second crank chambers 6 and 7, respectively. In this way, the temperature rise of the first and second crank chambers 6 and 7 is achieved. Is better prevented and the passage resistance of the cooling water is reduced.
[0030]
In the present embodiment, the internal combustion engine 1 also includes a cooling structure that uses traveling wind as a cooling source.
As shown in FIGS. 2 and 4, this air cooling structure has a cooling air passage formed in the left wall of the unit case 8 so as to go around the first and second crank chambers 6 and 7 in side view. (The hatched portion in FIG. 4) has 60, and the first and second interlocking gears 27 and 28, the primary drive gear 29, the primary driven gear 30 and the like are caused by the traveling wind flowing in the cooling air passage 60. The left wall portion of the unit case 8 that partitions the primary power transmission chamber 53 and the first and second crank chambers 6 and 7 is cooled, and heat from the primary power transmission chamber 53 toward these chambers is blocked. The temperature rise in these chambers is further prevented. The primary power transmission chamber 53 is covered with a left cover 54.
[0031]
The cooling air passage 60 has a cooling air inlet 61 in front of the left wall of the unit case 8 in front of the first and second crankshafts 22 and 25, and the first and second crankshafts 22 and 25. It has two cooling air discharge ports 62 and 63 that are further rearward and directed obliquely upward and downward in the rearward direction of the crankcase (the crankcase portion of the unit case 8).
[0032]
Cooling air (running wind) is introduced from a space C surrounded by first and second cylinders 4 and 5 that are respectively arranged in a diagonally up and down direction in front of the traveling direction of the vehicle on which the internal combustion engine 1 is mounted. It is introduced into the cooling air passage 60 through the port 61, flows along the sides of the first and second crank chambers 6 and 7 and around these chambers in a side view, and is cranked from the cooling air discharge ports 62 and 63. It is discharged in the diagonally up and down direction of the case.
[0033]
Since the present embodiment is configured as described above, the following effects can be obtained.
Surrounding the first and second crank chambers 6 and 7 of the two-cycle V-type two-cylinder internal combustion engine 1 having a transmission chamber 9 integrally behind the first and second crank chambers 6 and 7, respectively, 44, the heat from the mission chamber 9 is carried away by the cooling water, and the transmission to the first and second crank chambers 6 and 7 is greatly reduced. As a result, the temperature around the first and second crank chambers 6 and 7 is stabilized, the temperature rise of the air-fuel mixture in these chambers is prevented, the intake charging efficiency is improved, and the output is improved. Can do. In addition, since the temperature around the transmission chamber 9 is also stabilized, the durability of the transmission mechanism can be improved.
[0034]
In addition, the first and second crankshafts 22 and 25 of the two-cycle V-type two-cylinder internal combustion engine 1 having the transmission chamber 9 integrally behind the first and second crank chambers 6 and 7 are placed horizontally in the left-right direction. The cooling air inlet 61 is provided in front of the crankshafts 22 and 25, the cooling air outlets 62 and 63 are provided in the rear of the crankshafts 22 and 25, and the cooling air inlet 61 is directed to the cooling air outlets 62 and 63. Since the cooling air passage 60 through which the cooling air is passed is provided, heat from the mission chamber 9 and the primary power transmission chamber 53 is carried away by the cooling air and transmitted to the first and second crank chambers 6 and 7. Is suppressed. Thereby, the temperature rise of the 1st, 2nd crank chambers 6 and 7 is further prevented, the intake charge efficiency is further improved, and the output can be further improved. Further, the temperature around the mission chamber 9 is further stabilized.
[0035]
In addition, the cooling air passage 60 cools air from the space C surrounded by the first and second cylinders 4 and 5 that are respectively arranged in the diagonally up and down directions ahead of the traveling direction of the vehicle in which the internal combustion engine 1 is mounted. (Running wind) is introduced, cooling air is caused to flow along the sides of the first and second crank chambers 6 and 7, and the cooling air is discharged in the diagonally upward and downward directions of the crankcase. Therefore, the traveling wind is efficiently guided to the cooling air passage 60 and can contribute to the cooling of the crankcase, and the above effects are further promoted.
[Brief description of the drawings]
FIG. 1 is a left sectional view of an internal combustion engine to which a cooling passage structure according to an embodiment of the invention described in claims 1 to 5 of the present application is applied.
FIG. 2 is a cross-sectional view taken along the line II-II in FIG.
3 is a left side view of the internal combustion engine of FIG. 1 with the left cover removed.
4 is a cross-sectional view taken along the line IV-IV in FIG. 2;
5 is a partial right side view of the internal combustion engine shown in FIG. 1 with the right side cover removed, and also shows a modification of the cooling passage structure in the present embodiment. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine, 2 ... Internal combustion engine main body, 3 ... Transmission, 4, 5 ... 1st, 2nd cylinder, 6, 7 ... 1st, 2nd crank chamber, 8 ... Unit case, 9 ... Mission chamber, 10, DESCRIPTION OF SYMBOLS 11 ... 1st, 2nd intake passage, 12, 13 ... 1st, 2nd cylinder block, 14, 15 ... 1st, 2nd cylinder head, 16 ... 1st piston, 17 ... Scavenging port, 18 ... Combustion chamber , 19 ... exhaust port, 20 ... first spark plug, 21 ... first connecting rod, 22 ... first crankshaft, 23 ... second piston, 24 ... second connecting rod, 25 ... second crankshaft, 26 ... second ignition Plug, 27, 28 ... 1st, 2nd interlocking gear, 29 ... Primary drive gear, 30 ... Primary driven gear, 31 ... Main shaft, 32 ... Countershaft, 33 ... Sprocket, 34 ... Clutch, 35 ... Shift mechanism, 36 ... Cooling water pump, 37 ... impeller, 38 ... pump cover, 39 ... pump , 40 ... Pump discharge passage, 41, 42 ... Inlet water chamber, 43, 44 ... Cooling water passage, 45, 46 ... Intermediate water chamber, 47, 48 ... Water jacket, 49, 50 ... Cooling water outlet, 51, 52 ... Cooling water passage for short circuit, 53 ... Primary power transmission chamber, 54 ... Left cover, 55 ... Partition wall, 56 ... Cylinder bore, 60 ... Cooling air passage, 61 ... Cooling air inlet, 62, 63 ... Cooling air outlet, A , B ... mating surface, C ... space.

Claims (7)

A partition wall is formed between the crank chamber of the internal combustion engine and a transmission chamber integrally provided at the rear of the crank chamber with respect to the traveling direction of the vehicle, and from the intake passage side of the internal combustion engine, the cylinder of the cylinder block of the internal combustion engine A vehicle having a cooling water passage that surrounds the crank chamber and faces the partition wall so that cooling water flows toward an exhaust port facing the intake passage with respect to an axis . A cooling passage structure for an internal combustion engine. 2. The cooling passage structure for a vehicle internal combustion engine according to claim 1, wherein the crank chamber is a crank chamber for a two-cycle internal combustion engine that performs primary compression of an air-fuel mixture. 3. The cooling passage structure for an internal combustion engine for a vehicle according to claim 1, wherein the cooling water passage communicates with a water jacket formed in a cylinder block. The cooling water passage has a middle water chamber at a position facing the intake passage with respect to the cylinder axis and in the vicinity of the exhaust port, and the middle water chamber communicates with the water jacket of the cylinder block. The cooling passage structure for an internal combustion engine for a vehicle according to claim 3, wherein A partition wall is formed between the crank chamber of the internal combustion engine and a mission chamber provided integrally behind the crank chamber with respect to the traveling direction of the vehicle,
The crankshaft of the internal combustion engine is placed horizontally in the left-right direction,
A cooling air inlet is provided in front of the crankshaft and on the intake passage side, and a cooling air outlet is provided in the rear of the crankshaft.
A cooling passage structure for an internal combustion engine for a vehicle , wherein a cooling air passage for passing cooling air from the cooling air introduction port toward the cooling air discharge port is provided in contact with the partition wall . The cooling air passage introduces cooling air from a space surrounded by two cylinders that are respectively arranged in a diagonally up and down direction in front of a traveling direction of a vehicle in which the internal combustion engine is mounted. 6. The vehicle according to claim 5, wherein the cooling air is caused to flow along the direction of the crankcase, and the cooling air is discharged in a diagonally upward and downward direction of a crankcase forming the crank chamber . A cooling passage structure for an internal combustion engine. 7. The cooling passage structure for a vehicle internal combustion engine according to claim 6 , wherein the crankcase is a crankcase for a two-cycle two-cylinder internal combustion engine that supports a pair of parallel crankshafts.

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